Abstract: Drought is the major environmental factor that influences the growth of plant and accounts for significant reduction in the yields of crops. An effective approach to solve this problem is to produce drought-tolerant crops. Therefore, comparative functional genomics studies are required to identify key genes responsible for dehydration and drought stress tolerance as well as candidate genes for genetic engineering of drought stress tolerance in crop plants. Grimmia pilifera, as a common drought tolerant moss, grows in habitats of rocky outcrops, having a high ability in resisting drought stress. G.pilifera may serve as a rich genetic resource for the identification of novel genes associated with environmental stress and dehydration tolerance. To identify genes involved in drought tolerance for genetic engineering of biotic and abiotic stress tolerance in crop plants, a cDNA library was constructed with G.pilifera under drought stress by using Creater^TM SMART^TM cDNA Library Construction Kit. The total RNA was extracted by improved SDS method. The library had a titer of 2.8×10⁵ pfu·mL^-1, and the recombination rate was 91.7%. PCR amplification revealed that the insert cDNA fragments ranged mostly from 500 to 2 000 bp, with an average length of 800 bp. A total of 1 045 cDNA clones were randomly sequenced and analyzed. High-quality ESTs were obtained for 996 clones representing 875 unique sequences. The constructed cDNA library provided an essential for screening and cloning of new drought resistance associated genes of G.pilifera.

Key words: Grimmia pilifera, Switching Mechanism At 5&prime, end of the RNA Transcript(SMART), cDNA library, drought-resistance